摘要
采用固相烧结法制备了名义成分为 La1- x Kx Mn O3(x=0 .1～ 0 .4)和 La0 .8K0 .2 - yAgy Mn O3(y=0～ 0 .2 )的多晶样品 ,发现用 K、Ag取代 La后 ,可使菱面体结构的这种钙钛矿型稀土锰氧化物居里温度升高至室温附近 ,从而使样品的室温磁电阻增大 ,其中 La0 .8K0 .2 Mn O3在μ0 H =1 T磁场下的磁电阻可达 1 3.5%。该值比单纯掺 Na和掺 Ag的同样成分的稀土锰氧化物的磁电阻要大。通过对磁电阻与磁化强度之间密切关系的讨论 。
Polycrystalline samples of La 1- x K x MnO 3( x =0.1～0.4) and La 0.8 K 0.2- y Ag y MnO 3( y =0～0.2) were prepared by conventional solid state reaction processing in air. It is found that when La is substituted by K or/and Ag, the Curie temperature(T C ) of the perovskite manganites with rhombohedronal structure increases up to room temperature, and the r.t. magnetoresistance(MR) increases, of which the r.t. MR of the sample with a composition of La 0.8 K 0.2 MnO 3 is up to 13.5% at μ 0H= 1T , which is higher than that of the manganites only doping Na and Ag with same concentration. In addition, our results show that there is a close relationship between MR and magnetization. The microscopic mechanism of MR effect is discussed in this paper
出处
《磁性材料及器件》
CAS
CSCD
2001年第3期9-13,共5页
Journal of Magnetic Materials and Devices
关键词
钙钛矿型稀土锰氧化物
磁电阻
庞磁电阻效应
perovskite manganite
magnetoresistance
Curie temperature
double exchange
magnetization.
